Aeroengine Conversions
This page - a brief historical review The Big Questions: * Preliminary Choices * Which Type? I/II/III or IV? * Which End to Mount the Propeller? * Reduction Gear or Direct Drive? * Starter? Dynamo? * U-Build, Kit, or Completed Engine? Details: * Deeper into the choices to be made. * Aviation Specific Vendors and Their Products ---- Since the end of World War II, enthusiasts have been using VW engines to power light airplanes. Blame it on the French R.S. Hoover tells this tale: During World War II, Volkwagenwerk cranked out about 50,000 Type 62's, commonly called the 'Bucket Car' or Kubelwagen. The kubel was designed in 1938 and powered with the standard 985cc 'E-motor' (73mm bore x 64mm stroke) developed by Reimspeiss in 1935, rather optimistically rated at 23 horsepower. To gain the needed ground clearance and torque for running off pavement, the standard VW tranny was fitted with outboard gear reduction units, which survived until 1967 in the VW Transporter. ''In 1940 Volkswagen was tasked with developing an amphibious 4WD version of the kuble -- the Type 162. commonly called the Schwimmwagen. To power the Schwimmer, of which about 14,000 were built, VW bored out the E-motor to 1131cc (75 x 64), creating the so-called 'big engine'... rated at a whopping 25hp :-) The 1100cc powerplant became the standard VW engine and was used through the 1954 model year. ''Fitted with the Big Engine, the Type 62 became the Type 82 (still called the 'Kubelwagen, however) but initially all 'big engine' production was devoted to the Schwimmer and other 4WD variants, including the command-car version of the kubel. ''The point of all this is to make clear that, following the war, there were lots of Kubels left sitting about Europe (and still are!), many of which were fitted with the less desirable 'small engine'. (Nobody wanted the small 22hp engine when they could enjoy the neck-snapping torque of a Big Bore 25hp engine... even if the difference was mostly myth. Come to think of it, things haven't changed all that much :-) '' ''Enter now Messrs. Druine and Jodel, who took one look at all those free 22hp aircooled engines littering the landscape and promptly designed a couple of small, single-place LIGHT airplanes. The engine was small enough and light enough and smooth enough so that a regular engine mount wasn't needed -- they bolted the thing directly to the firewall, stuck a pair of wheelbarrow wheels underneath and flew off into the history books. By the late 1950's the RSA (French equiv. of the EAA) reported (reasonable accuracy assumed) that their VW powered designs had accumulated more than 20,000 flight-hours. And still are. Plans for the RSA conversion are still available via Falconar Avia Early US Experience Hugh Beckham fills in his bit of history: In the late 1950s and early 1960s there were a few airplanes flying in Europe with the 1200 CC VW engine of the day. Among these were the Druine Turbulent, a very complex airplane with wing slots and a very difficult to build wing and fuselage. The Turbulent was designed to be a flying club time builder which would spend it's entire life within falling distance of home field. It was slow, required long smooth airfields in order to leave the ground, and had a rate of climb that was so slow as to be the subject of many jokes. It was however considered to be safe enough that Prince Charles was allowed to fly one. Another European design, The Jodel Bebe D9 was designed specifically for the 1200CC VW engine. It was an easier airplane to build and was considered to be a better all around design than the Druine however the design was of French origin and the drawings were in French and metric. At that time there were none of either design being built in the US. There were quite a number of those self proclaimed authorities who talk a lot but never accomplish anything who were just sure that the only way to fly with a VW engine was to have acres and acres of wing and to fly very slowly. Bob Whitier, who is still writing articles for The Experimenter was a leading outspoken enemy of small engines in aircraft. A fellow named Richard Doyle built a Gyrocopter based on the Gizmo design and fitted it with a VW but was not able to fly. He later removed the rotor. added a wing, and called the machine Moon Maid. It is still a regular at Oshkosh. Moon Maid is slow, and in my opinion not very attractive, and I think will never be duplicated. After all of these years Dick has modified the engine many times and gone to larger and larger engines. In California's Central Valley, Veeduber was re-engining an Aeronca C-2 with a VW, perhaps as early as 1955, but his activities (he was a teenager at the time!) didn't register much South or East of Turlock. ;-) In 1960 I built a Taylor Mono, the first to be built from plans, and converted a 1200 CC VW engine for aircraft use. My approach to the engine conversion was based upon the theory that the engine had originally been an aircraft engine and could be converted back to that use. With that engine I had an airplane that would operate easily off of a grass field, climb at 650 FPM, cruise at 105 MPH at 3050 RPM and top out at 120 MPH. Hugh restates a common mis-conception here about the VW engine. Common airplane engines at the time the VW engine was designed looked NOTHING like it. They tended to be either radials, or inline or vee-form, and frequently liquid cooled. The first horizontally opposed air-cooled 4 aeroengine, the Continental A-40, had just made the leap from railway work car engine. And the VW engine was designed as a car engine - consult any history of the VW if you have any doubt. I made up a set of drawings < for his VW conversion, not the plane itself > and advertised them in Sport Aviation for $2.00 a copy. Remember that EAA was a very small organization at that time but even so I sold over 500 copies including a set to John Monett. I had no interest in profiting from what I had done for the fun of it and so I donated the plans to EAA. They were published sometime in the mid 60s under the title, "Put a Beetle Under Your Bonnet". New Designs Emerge The Tipsey Nipper, Belgium's contribution to General Aviation, first flew in 1957. In France, starting in 1960, Rene Fournier was starting to build his series of beautiful wooden motor gliders, the first of which was powered by what was likely an Ardem conversion similar to what was flying in some numbers on designs by Piels, Druine, and JoDel. Later production versions used Rectimo, STAMO, and Limbach conversions, and by the 1966 introduction of the RF-4D, this was a mature, reliable design. Miro Slovak twice crossed the atlantic in one, and deliveries to Africa were common. Bob Hugins of Tulsa, Oklahoma, was working on and publishing information on conversions in the mid-1960's. In the US, the boom in use of the VW as an aeroengine came with the Mini Ace (Anton Cvjetkovics CA-61), the Evans VP-1 (it's original designation, the Volksplane, was nixed by VWoA) and Calvin Parker's Jeanie's Teenie, and it's much more successful followup, the Teenie Two. The Mini Ace first flew in 1965, VP-1 in 1968, Jeanie's Teenie perhaps in 1967, and the Teenie Two in 1969. All were featured on the covers of national magazines (Popular Mechanix, Mechanics Illustrated) and sold thousand and thousands of plans. They used very simple conversions, much like the early european designs, Vertex magnetos, hand prop, bolted directly to the firewall. Markets Beget Marketers Joe Horvath had been a VW hot-rodder and engine rebuilder for a number of years, and in about 1967, he sold his high volume rebuilding shop, and dedicated his attentions to developing the VW as an airplane engine. He started to sell complete engines, WITH electric start, generators, carbs under the engines, and real aircraft magnetos in 1968. There were other smaller operators (including Veeduber, and Chris Falconar in Canada) selling completed engines, but Revmaster, Joe's company, was the first to sell in any volume, and his style of conversion (accessory case, carb under, prop drive from the fan end) set the model for most later engines. Stu Robertson and Ken Rand started work on the prototype KR-1 about this time; it first flew in 1972, and created quite a sensation, again, selling thousands of plans. VW engines were also finding application in Bensen gyrocopters. For an overview of these and the many other designs flying with VW power, see http://users.lmi.net/~ryoung/Sonerai/rant.html * Preliminary Choices * Which Type? I/II/III or IV? * Which End to Mount the Propeller? * Reduction Gear or Direct Drive? * Starter? Dynamo? * U-Build, Kit, or Completed Engine? Details * Deeper into the choices to be made. * Aviation Specific Vendors and Their Products